Semiconductor memory devices, in particular, Random Access Memory (RAM) devices, are increasingly being used in mobile electronic devices. Since mobile electronic devices generally rely on batteries for power, rate of power consumption is an operation parameter of such devices that is closely monitored.
In response to such monitoring, semiconductor memory devices have been designed with low power consumption modes (for example, a deep power down mode during which a device is powered but does not retain data or allow access to stored data).
In general, a low power consumption mode acts as an alternative to a normal mode, in which normal operations, such as data read operations and data write operations, are required. Activation of the low power consumption mode may be triggered in a semiconductor memory device when the semiconductor memory device has not been accessed for a read operation or for a write operation for a predetermined duration.
When in the low power consumption mode, most of the internal circuitry of a respective semiconductor memory device is rendered in a “standby” state to reduce the power consumption inherent in maintaining the internal circuitry in a “ready” state.
Unfortunately, even in the low power consumption mode of operation, a semiconductor memory device can allow a flow of so-called leakage current. The leakage current of many circuits can add up quickly and result in substantial, undesirable power losses.
Some time ago, the leakage current was insignificant relative to the operating currents. However, as the size of the internal circuitry has been reduced, the significance of the leakage current has increased. Accordingly, it is becoming increasingly desirable to identify sources of leakage current and provide new ways to reduce such currents.
Similar or same reference numerals may have been used in the different figures to illustrate similar components or resources.